CVE-2026-124864: Mozjs52 · Sandbox escape due to use-after-free in the DOM: Service Workers component
Affects mozjs52Source GCVE Database
Not known to be exploited · CVSS 9.6 Critical.
Data as of 13 Nov 2026, 22:50 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 9.6 |
|---|
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSmozjs102pkg:deb/ubuntu/mozjs102?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSmozjs115pkg:deb/ubuntu/mozjs115?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSmozjs102pkg:deb/ubuntu/mozjs102?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSmozjs78pkg:deb/ubuntu/mozjs78?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSmozjs91pkg:deb/ubuntu/mozjs91?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSthunderbirdpkg:deb/ubuntu/thunderbird?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and has been released in Firefox 160, Firefox ESR 115.45, Firefox ESR 153.7, Thunderbird 160, and Thunderbird 153.7. Users and administrators should upgrade to these or later versions to remediate the vulnerability. No additional mitigation actions are required beyond applying the official patches.
Description
CVE-2026-124864 is a critical use-after-free vulnerability in the DOM Service Workers component of mozjs52. It allows sandbox escape, potentially enabling an attacker to break out of the browser's sandbox environment. This vulnerability was fixed in Firefox 160, Firefox ESR 115.45, Firefox ESR 153.7, Thunderbird 160, and Thunderbird 153.7.
References
- ubuntu.com/security/CVE-2026-124864 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-124864 (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-125/ (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-127/ (opens in a new tab)
- mozilla.org/en-US/security/advisories/mfsa2026-129/ (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=2075976 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-125/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-126/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-127/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-128/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-129/ (opens in a new tab)